Mechanochemical Synthesis of Porous Carbons and Their Applications in Catalysis

Abstract

Porous carbons have shown considerable potential in catalysis as either as supports or metal-free catalysts. Various methods based on solution chemistry have been intensively developed for the preparation of porous carbon-based catalysts with controllable morphology, pore structure, surface chemical property as well as the desired active sites. Nowadays, mechanochemical synthesis, a re-emerging strategy, has become more and more popular in the synthesis of porous carbons, due to its feasibility and high synthetic efficiency under solvent-free condition. This Minireview presents recent advances in the mechanochemical synthesis of porous carbons by ball milling, and their applications in catalysis. It starts a brief introduction of the characteristics and work mechanism of ball milling, and then discuss the preparation of porous carbons as metal-free catalysts and carbon-supported metal catalysts. Finally, some issues and further opportunities for the mechanochemical synthesis of porous carbon-based catalysts are proposed and discussed.

Mechanochemical Synthesis of Catalytic Materials

“…The finding of Zhang et al. that ball milling can sustain the coordinative cross‐linking polymerization of tannin with divalent metal ions (as metal acetates, e.g., Zn 2+ , Ni 2+ , and Co 2+ ) in the presence of a template (e.g., Pluronic triblock copolymers) lead to the synthesis of various ordered mesoporous carbons [75] . Indeed, the use of templates with different compositions simply enabled the synthesis of mesoporous carbons with tuneable pore sizes, ranging from 4 to 10 nm, after carbonization of the gel nanocomposite [76] .…”

Mechanochemical Synthesis of Ammonia Employing H2O as the Proton Source Under Room Temperature and Atmospheric Pressure

“…Mechanochemistry promotes chemical reactions through the mechanical force obtained by grinding, shearing, stretching, and so forth 18−20 and is widely applied in organic synthesis 21,22 such as ladderane/ene, 23 metal−organic frameworks, 24 and deep eutectic solvents; 25 inorganic synthesis like noble metal nanoparticles, 26 supported metal catalysts, 27 and γ-graphyne; 28,29 gas synthesis 30 such as CH 4 , 31 CO 2 , 32,33 and CO; 34 highly porous materials; and so forth. 35,36 In as early as 1996, Mori et •h −1 under 45 °C and 1 bar, demonstrating that the mechanochemistry is a promising nitrogen fixation technology. 38 The NH 3 synthesis process was divided into two steps of nitrogen dissociation and hydrogenation; it successfully elucidated the mechanism of gas phase mechanochemical synthesis of NH 3 in detail (Figure S1a).…”

“…Mechanochemistry promotes chemical reactions through the mechanical force obtained by grinding, shearing, stretching, and so forth − and is widely applied in organic synthesis , such as ladderane/ene, metal–organic frameworks, and deep eutectic solvents; inorganic synthesis like noble metal nanoparticles, supported metal catalysts, and γ-graphyne; , gas synthesis such as CH 4 , CO 2 , , and CO; highly porous materials; and so forth. , In as early as 1996, Mori et al reported methanation of CO 2 in the ball mill and revealed the value of continuous heterogeneous catalyzed gas-phase reactions under ball milling conditions, demonstrating that Ru–MgO and Ni–Fe–MgO are superior to other evaluated catalysts in facilitating the mechanochemical methanation of CO 2 in a ball milling process . In 2011, Mulas et al demonstrated the mechanochemical hydrogenation of carbon monoxide over FeCo- and Mg 2 Ni-based catalysts, confirming that the mechanical activation at 300 K and 0.6 MPa outperformed standard thermal methods (400–800 K, 2–5 MPa) by realizing similar or higher conversion .…”

Mechanochemical synthesis of alumina-based catalysts enriched with vanadia and lanthana for selective catalytic reduction of nitrogen oxides

“…These parameters are of particular importance in the design and preparation of advanced materials for a range of catalytic applications. There are many reports on the use of mechanochemical protocols to obtain various catalysts (supported metal nanoparticles, nanocomposites, and nanomaterials) with improved catalytic activity and selectivity 24 , 26 , 27 , demonstrating the potential of this method to provide more sustainable routes for the preparation of catalysts 28 .…”